KR20220074818A - infrared toaster - Google Patents

Abstract

An infrared toaster and toasting method uses a support configured to hold food against an infrared source. A light source and camera are arranged relative to the support to illuminate the food and capture digital images of the food. The processor receives and analyzes successive images from the camera. The processor activates the IR source to achieve a predetermined toasting level of the food product. The processor activates the IR source to end directing the IR energy when a predetermined toasting level is reached.

Description

infrared toaster

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application No. 62/817,277, filed March 12, 2019, and U.S. Provisional Patent Application No. 16/814,414, filed March 10, 2020, the contents of which are incorporated herein by reference. is incorporated by reference in its entirety.

Many restaurants offer toasted bread and toasted English muffins as regular menu items. Many other menu items include sandwiches made up of toasted baked goods including toasted bread slices, buns, bagels or English muffins.

Toasted food has a distinctly different flavor than the same product before toasting. Toasting food also changes the color and texture of the bread product. In addition to altering flavor, color and texture, the toasting process often provides a pleasing aroma.

Toasting food products such as sliced breads, English muffins, bagels, pizza crusts and other baked goods is generally accomplished using radiant or conductive energy transfer from one or more heat sources to the baked goods. The toasting process, also referred to herein as browning, is the result of a chemical reaction known as the Maillard reaction. The Maiard reaction is a reaction between a carbohydrate and a protein that occurs upon heating and produces browning.

If the Maiard reaction is too far or too long, it is believed that the carbohydrates in the bread product are completely oxidized to form carbon. Carbon absorbs light. Accordingly, the surface of the burnt bread product appears black. Thus, the term "burn" means that the carbon content of the surface of the bread product is sufficient to absorb visible light that strikes the surface of the bread product and makes the surface, or part of the surface, of the bread product appear black to the average viewer. It is considered a heat-induced oxidation of carbohydrates to a sufficiently high point.

A well known problem with prior art toasters of all kinds is that it is often not possible to consistently achieve uniform toasting across the bread product surface at the same time. Bread products, such as English muffins, are toasted uniformly and consistently in a short period of time because of their mass, surface irregularities and temperature, especially because the peaks and valleys of the English muffin surface are at different distances from the IR source triggering the toasting process. it is difficult Because many restaurant operators need and prefer to be able to toast bread products such as English muffins as quickly as possible, attempts to shorten toasting times simply by increasing the input infrared energy are typically to toasting more bread products. resulting in more burning. An improvement over the prior art is a toaster and method of toasting foods such as bread and English muffins that can provide a consistently uniform browning in a relatively short time.

An example of a toaster includes a support configured to hold food. An infrared (IR) source is arranged relative to the support. The IR source is operable to direct IR energy to the food on the support. A light source is arranged relative to the support. The light source may be operable to illuminate the food product on the support, and the IR source is operative to direct the IR energy. The camera operates to capture a digital image of the food product on the support. A processor receives an image from the camera. The processor analyzes successive images received from the camera. Based on the analysis of successive images, the IR source is activated to achieve a predetermined toasting level of the food product. The processor activates the IR source to end directing the IR energy when a predetermined toasting level is reached.

In another example of a toaster, a light source operates to illuminate the support and the processor analyzes the digital image from the camera to determine the presence of food on the support. The processor determines a current toasting level of the food product from the successive images received from the camera based on the amount of light in the at least one test spectrum in each successive image. The processor analyzes the digital image from the camera to determine an initial color of the food product on the support, and the processor determines a weight for the at least one test spectrum analyzed by the processor to determine the current toasting of the food product. The at least one test spectrum may include a green light test spectrum and a red light test spectrum. The weight for the red light test spectrum may increase as the darkness of the initial color of the food increases. The current toasting level of the food product may be determined by the processor further based on the brightness compensation factor for the at least one test spectrum. The processor may calculate at least one brightness compensation factor based on a reference brightness for at least one test spectrum determined from a portion of an initial image of the food product acquired by the camera. A part of the initial image may be a part that does not include food. The at least one brightness compensation factor may further be calculated based on the current brightness for the at least one test spectrum determined from the same portion of a subsequent image from the camera.

Another example of a toaster may include an image tearing mask. The processor may apply an image tearing mask to each successive image received from the camera and pass or reject the image for use in determining the current toasting of the food product based on application of the image tearing mask. The toaster may include a predetermined static mask. The processor may apply a static mask to the image received from the camera to limit the portion of the received image that is analyzed to determine the current toasting of the food product. The toaster may determine the dynamic mask based on at least one image of the food product received from the camera. The dynamic mask includes the calculated at least one boundary of the food product in the at least one image and the processor applies the dynamic mask to the image received from the camera to limit the portion of the received image that is analyzed to determine a current toasting of the food product. apply

Additional examples of toasters may include a support and an ejector operatively coupled to the processor. The processor may actuate the ejector to remove the bread product from proximity to the IR source when a predetermined toasting level is reached. The toaster may include an IR source configured to be annular and the camera positioned at the center of the IR source. The camera may include a wide-angle lens. The camera may be recessed from the outer surface of the IR source in a direction away from the bread product. The light source may be positioned in the center of the IR source and adjacent to the camera. The toaster may include a forced gas source and a duct that opens around the camera between the camera and the IR source to create a forced gas flow around the camera.

The toasting method illustratively includes holding the food product on a support relative to an infrared (IR) source. The IR source is operated to direct IR energy to the food on the support. Food is illuminated on the support. A digital image of the food on the support is acquired with a camera. Successive images acquired by the camera are analyzed to determine a current toasting level of the food product based on the amount of light in at least one test spectrum in each digital image acquired by the camera. A time is determined when a current toasting level of the food product reaches a predetermined toasting level of the food product. The IR source is operative to terminate the directing of the IR energy to the food product when a predetermined toasting level of the food product is reached. The method may include determining an initial color of the food product by analyzing an initial image from the camera and determining, based on the initial color, a weight for at least one test spectrum to determine a current toasting level of the food product. can The method includes determining a reference brightness for at least one test spectrum from a portion of an initial image that does not include food, determining a current brightness for at least one test spectrum from the same portion of a subsequent image from the camera, the reference calculating a brightness compensation factor for the at least one test spectrum from the brightness and the current brightness, and further using the brightness compensation factor for the at least one test spectrum to calculate a current toasting level of the food product. can do.

1 is a system diagram of an exemplary embodiment of a toaster;
2 exemplarily illustrates the level of toasting doneness.
3 is a flowchart of an exemplary embodiment of a toasting method;
4 shows an exemplary embodiment of a toaster in a horizontal configuration.
5 is a system diagram of a toaster in a horizontal configuration.
6 shows an exemplary embodiment of a toaster in an inclined configuration.
FIG. 7 is a cross-sectional view taken along line 7-7 of FIG. 6 .

1 shows an exemplary embodiment of a toaster 10 . The toaster 10 uses at least one infrared (IR) source 12 , and illustratively uses two IR sources 12 as shown in FIG. 1 . An IR source may exemplarily take the form of a coil of charged wire, which is known to heat up and release IR energy when excited with an electric current. It will be appreciated that there are other sources of IR energy that may be used in other embodiments including, but not limited to, one or more IR emitting LEDs, for example, an array arrangement of IR emitting LEDs. IR source 12 is arranged to direct IR excitation 14 at food 16 . 1 , and as described in greater detail herein, IR source 12 may be configured and/or operated as a toasting IR source 12A and heat source 12B, and is an exemplary IR emission source. Additional disclosure and description of the toaster as well as its components and operation is provided in Applicant's co-pending U.S. Patent Application Publication No. 2019/0387926 entitled "Infrared Toaster," which application is incorporated in its entirety. incorporated herein by reference. Combinations of features disclosed in this application with features disclosed herein will be recognized based on this disclosure.

The toaster 10 of FIG. 1 exemplarily provides an embodiment for toasting one side of a food product 16 , ie a toasting surface 18 arranged proximate the toasting IR source 12A. In this embodiment, heat source 12B provides additional thermal energy to the toasting system to raise the overall temperature of the toasting system during operation. This embodiment may toast the second side of the food product 16 by performing a second toasting cycle on the food product 16 once the food product 16 is turned over in the toaster 10 . In another embodiment, two toasting IR sources 12A may be arranged in the toaster 10 to simultaneously toast both surfaces of the food product 16 . The food product is illustratively a bread product desired to be toasted, although heat treatment, illustratively cooking, searing, broiling, or baking may be achieved in other embodiments. Bread products may include, but are not limited to, sliced bread, English muffins, bagels, pizzas, flat breads, rolls or buns. In another embodiment, a whole or partially complete sandwich or sandwich portion (eg, open sandwich halves) may be toasted. In another embodiment, the toaster is operable to melt cheese placed over the bread product.

In an embodiment, the toasting IR source 12A is comprised of one or more sensors as described herein directed by the IR source to a toasting surface to be toasted. The toasting IR source 12A is arranged close to the toasting surface and generally operates at a higher thermal energy output. This is compared to heat source 12B, which may be a heating IR source but may not include an associated sensor, or at least a toasting sensor as described with respect to toasting IR source 12A. Moreover, the heating IR source 12B may not be directed to the toasting surface and further may be operated at a generally lower thermal energy output. In the example, toasting IR source 12A is configured to direct IR energy to the surface of food product 16, illustratively by radiant heat transfer, while heat source 12B is radiative, conductive, and/or convective heat transfer. can be configured to heat the food 16 and the entire interior of the toaster.

In an example, toasting IR source 12A may include a resistive wire coil that is exposed toward toasting surface 18 of food product 16 to generate and direct IR excitation at toasting surface 18 . The heat source 12B may also include a resistive wire, but the food may be shielded from the resistive wire. In an example, a glass layer and a stainless steel layer may be interposed between the resistive wire and the food product. This dissipates heat from the resistive wire of heat source 12B to increase the temperature inside the toaster and helps to increase the temperature of the food, but provides limited toasting of the food or no toasting of the food at all.

As previously mentioned, the challenge for toasting equipment is to provide food 16 to achieve a desired level or amount of toasting outside of the food without over-toasting or under-toasting the food within a narrow quality range. It is to provide an amount of energy quickly. Moreover, it would be desirable to provide a toasting apparatus and method in which a certain level of toasting is consistently achieved. In another exemplary embodiment, it would be desirable to provide a toasting apparatus and method in which this particular level of toasting is achieved consistently across a variety of food types. Foods, more specifically baked goods, differ in a variety of physical properties, and examples of physical properties in which baked products differ include surface area (A), thickness (T), and initial color (C).

2 provides an example of varying levels of toasting build-up for various examples of baked goods. The example provided in Figure 2 is arranged with the same type of baked goods oriented in horizontal rows, with the vertical rows each representing the level of toasting achieved across each type of baked product. 2 provides examples of five different toasting levels, more or fewer levels may be used in different embodiments and the range between levels may be wider to include more and less toasting. It will be recognized that there is

Referring again to FIG. 1 , toaster 10 includes features described in more detail herein to control the toasting process of food product 16 and to rapidly toast the food product to a desired toasting level and to The operation of components of the toaster 10 that terminates the toasting process can be closely monitored to ensure that the toasting level is not exceeded.

The toaster 10 includes at least one sensor oriented relative to the food product 16 and directed towards the toasting surface 18 of the food product, eg a camera 20 . Although the camera 20 is shown in FIG. 1 in a generalized form, more specific illustrative embodiments of such a camera arrangement will be disclosed in greater detail herein and embodiments of the toaster 10 than those provided in the examples herein. It will be appreciated that other camera 20 features may be included. Camera 20 exemplarily acquires a digital image capture of the toasted food surface and provides this digital image capture to processor 22 for analysis and resulting control of IR source 12 .

1 shows the camera 20 in a position arranged in the center of the toasting IR source 12A and directed towards the toasting surface 18 of the food product 16 . Illustratively, toasting IR source 12A is an annular shape with camera 20 positioned inside toasting IR source 12A. As will be described in greater detail herein, it is desirable to protect the camera 20 from the heat of the IR source 12 , so that the camera 20 is heated by the heating element 24 of the toasting IR source 12A. is indented from However, as described herein, it is desirable for the field of view 25 of the camera 20 to be wide so that the digital image captured by the camera 20 includes at least a large portion of the toasting surface. Accordingly, there is a limit to the distance the camera 20 can be recessed with respect to the toasting IR source 12A. In some embodiments, the digital image may capture a field of view extending beyond the perimeter of the food product, while in other embodiments the digital image may capture a field of view that includes only a portion of the toasting surface.

To produce an accurate analysis of the food toasting, an auxiliary light is projected onto the toasting surface 18 . This auxiliary light is provided by one or more light sources 26 . Light source 26 is illustratively an LED light source arranged proximate to camera 20 , for example in the center of toasting IR source 12A. In other embodiments, the light source 26 may be located at another location, for example on the side of the toaster 10 ; However, it has been found that increasing the relative angle of the light source 26 in a direction perpendicular to the toasting surface 18 improves illumination of the toasting surface 18 by the light source 26 . Light source 26 may be operable to emit visible spectrum light, IR spectrum light, UV spectrum light, or a particular wavelength or combination of wavelengths within this range according to a particular embodiment as described herein. Exemplary and non-limiting embodiments may project a green spectral wavelength of visible light, a red spectral wavelength of visible light, an IR spectral wavelength of light, or any visible spectral wavelength of light (eg, white light).

As mentioned above, it is desirable to protect the camera 20 from excessive heat generated by the heating element 24 of the toasting IR source 12A. Additionally, the inventors have confirmed that the temperature of the light source 26 can change the intensity of the light produced, thus leading to detection errors as described in more detail herein. Additionally, it is desirable to limit the overall exposure of the light source 26 to excessive heat. An air source, which may be a blower 28 , but other sources of air movement recognized by those skilled in the art, directs the flow of air around and past light source 26 and camera 20 .

Air flowing past the camera 20 in the direction of the food 16 also protects it from collecting grease, condensation, food particles, dust, or other contaminants that may obscure or obscure images captured by the camera 20 . An air shield that protects the camera 20 is created around the lens of the camera 20 . However, this air flow can also have a negative effect on locally cooling the food product 16 at the location of this air flow. Accordingly, an air chamber 30 configured around the camera 20 and light source 26 enables circulation of air to the camera and light source 26 . This cools the camera 20 and light source 26 and warms the air that is directed past the camera 20 towards the food product 16 . The air chamber 30 also exhausts some of the air circulated away from the food 16 out of the air chamber 30 .

Food 16 is supported between IR sources 12 by food supports 32 . Embodiments of food support 32 may take a number of forms, as described in greater detail herein, and operate in such forms to facilitate loading and unloading of food 16 to toaster 10 . It may be possible. The food support 32 holds the food 16 in the toaster 10 in a predetermined position relative to at least the camera 20 and the toasting heat source 12A. The food support 32 may be, but is not limited to, a grate, door, platform, or conveyor. As will be described in greater detail herein, the ejector 34 may further be actuated by the processor 22 to facilitate mechanical ejection of the food product to quickly end the toasting process.

Processor 22 is, for example, a computer program or It is communicatively coupled to a computer readable medium (CRM) 36 having computer readable code stored thereon in the form of software. It will be appreciated that the processor 22 is illustratively integrated into any of a variety of known controller circuits, integrated circuits, microcontrollers, or related circuitry. The processor 22 may be part of a central processing unit (CPU) including integrated memory, although in embodiments the CRM 36 may be a separate component or communicatively coupled to the processor 22 . . Processor 22 accesses software or firmware in the form of computer readable code stored in CRM 36 as integrated memory or external memory. Processor 22 executes computer readable code as a set of instructions for performing the functions described herein, including receiving inputs, calculations, and outputs to be described. Processor 22 receives digital image captures from camera 20 and monitors the toasting process using image processing techniques as described in more detail herein to achieve a desired toasting level of food product 16 . provide operating commands to the components of the toaster 10 in this manner.

The processor may also be communicatively coupled to a source 38 of models or algorithms, which may be stored on a non-transitory computer readable medium, such models being used for the particular type of food to be toasted or the particular requested toasting operation. You can define parameters or algorithms. Examples of equations that may be used during the operational process are provided herein, and such equations may be stored on a non-transitory computer-readable medium. Model 38 may include various toasting level models that may be represented as curves of determined reflected light from food products representing various toasting levels. Model 38 may be stored locally on processor and toaster 10, or may be stored at a remote location and the communication connection may instead span a local area network or wide area network. As will be described in greater detail herein, the processor 22 may select from information stored in the source of the model 38 when receiving input or detecting a particular condition. It will be appreciated that this may also be stored in CRM 36 .

The toaster 10 may include a user interface 40 through which the toaster 10 receives one or more user inputs for controlling a toasting operation. In an exemplary embodiment, the user interface 40 may be a physical button or may be a touchable graphical display. In another embodiment, the user interface may be provided to a personal computing device communicatively coupled to the toaster 10 via, for example, Wi-Fi or Bluetooth communication protocols. Examples of input that can be received include single-sided or double-sided toasting; identification of the food product, and the desired level of toasting.

In yet another embodiment, the processor 22 of the toaster 10 manages, for example, customer orders, order completion status, monitors inventory levels and operation of devices in the kitchen, and/or provides access to devices in the kitchen. It may be communicatively coupled to a kitchen management system (KMS) 42 , which may be illustratively a locally implemented or remotely implemented computer system that operates to provide operating instructions. In an exemplary embodiment, the communication link between the processor 22 and the KMS 42 allows the KMS to provide the user with operating instructions, eg, the type of food to be toasted, the noodles of the food to be toasted, and the level of toasting to be achieved. Alternatively, it may be provided to the processor 22 without additional input from an operator. Although not shown, a food dispenser, such as a baking product dispenser, may be operatively coupled to the toaster 10 and communicatively coupled to the KMS, and coordinated operation between the devices ensures that the appropriate baked product is delivered to the toaster 10 . can be automatically loaded into the toaster 10 and operation of the toaster 10 to achieve a desired toasting level of the baked product.

3 is a flow diagram illustrating an exemplary embodiment of a method 100 for toasting food products, such as those shown and described above in connection with FIG. 1 and in connection with the exemplary embodiment of a food product of baked goods. Reference will be made to the toaster 10 in more detail herein. Method 100 begins with bread being received into a toaster at 102 . The toaster also receives a desired toasting level for the bread. This may be a preset toasting level, for example if the toaster is configured to provide the same toasting level in each toasting operation. Alternatively, the desired toasting level may be entered by the user or received from the KMS as described above. In another exemplary embodiment, a received piece of bread may be identified and the specific identification of the bread (eg, white bread, wheat bread, rye bread, bagel, English muffin, or bun) will have a preset associated toasting level. can The toasting level may be defined as one or more curves or functions of the amount of light determined as described in more detail herein.

At 104 , the toaster illuminates the toasting chamber with red light. The system determines whether food has been loaded into the toaster. The inventors believe that because red light provides contrast between food and toaster interiors over a wide range of food types, shapes, and initial colors, red spectral light determines whether a toasting chamber is empty or has received baked goods to be toasted. found useful for If an identification of the baked product has not yet been received, the system can determine an initial color of the baked product at 106 . In doing so, the bread is illuminated at 106 and an image of the illuminated bread is captured and a determination of the initial color of the bread is made at 106 . In some embodiments, this illumination may be white light or may use a subset of the visible light spectrum for illumination purposes. In one embodiment, red light illumination may be used for contrast between the different initial colors of the available bread. In some embodiments, the red spectrum of light may be useful for both light colored and dark colored bread, and also helps the system to distinguish the presence of bread in a toaster from an empty toaster.

When used to evaluate toasting progress and toasting levels, based on the initial color of the food, different spectra of light may or may not produce desirable results. In an example, a combination of one or more of green spectral light, blue spectral light, and red spectral light may be used in toasting analysis. In a further example, analysis of green spectral light and red spectral light may be used. At 108 , a weight for each test spectrum is determined. In an example, the weight may be a function of the determined initial color of the food product. Food initial color may be normalized based on the expected food initial color range. The determined initial color of the food product may be compared to one or more thresholds associated with different weights. In another example, the weight for each light test spectrum is determined by a function. It will be appreciated that a weight of 0.0 may have the effect of a test spectrum not being used in the decision. It will further be appreciated that weights may have the effect of only a single test spectrum used for determination. In general, the red light test spectrum is beneficial when determining toasting foods with a darker initial color, such as black rye bread, and the green light test spectrum is useful for toasting foods with a lighter initial color, such as white bread. favorable for decision

As described in greater detail herein, the toasting decision may be calculated based in part on the following equation, where parameters W _G , W _B and W _R apply for each of the green, blue and red test spectra is each weight.

here:

MC = Mask Compensation Factor

BFNBG = Brightness Factor Non Bread Green

BFNBB = Brightness Factor Non Bread Blue

BFNBR = Brightness Factor Non Bread Red

RBNBR = Reference Brightness Non Bread Red

RBBR = Refrence Brightness Bread Red

RBBG = Refrence Brightness Bread Green

RBBB = Refrence Brightness Bread Blue

CBBR = Current Brightness Bread Red

CBBG = Current Brightness Bread Green

CBBB = Current Brightness Bread Blue

RDN = Raw Doneness Value

Returning to 110 , after the bread has been identified, the bread may be illuminated with white light at 110 . White light is used to evaluate the toasting level in the toasting process. It will be appreciated that in embodiments where white light (or the same light spectrum) is used to illuminate food at 106 to determine the initial color of the food, then 106 and 110 can be effectively combined. This will be the case in other examples where the same light spectrum is used to illuminate food not only for initial color determination, but also to monitor toasting progress. As described above, it will be appreciated that alternative colors or combinations or separate colors or colors of the illumination light wavelength including, but not limited to, illumination using light of the green spectral wavelength may be used in other embodiments. Test spectra of red, green and/or blue wavelengths are described in the examples herein. It will be appreciated that in other embodiments, other selected test wavelength spectra may be used, including, but not limited to, yellow, orange, purple, infrared or UV spectra. In an example, particularly identified baked goods may be analyzed for toasting with a combination of these test wavelength spectra and different identified baked products, or baked products with specific properties may be analyzed with these different combinations. As described above, the use of specific test spectral wavelengths may be adjusted to weight the various test spectra based on the identification of the baked product or the identification of the characteristics of the baked product.

At 112 , the heat source is activated. As described above, the heat source may be illustratively a wire coil that, upon receiving electrical excitation, heats up to a glowing temperature at which the coil emits IR radiation towards the bread held in the toaster. As previously mentioned, in embodiments of the toaster, the toaster may be configured to toast one side of the received bread, the heat source opposite to the bread from the toasting side of the bread being the bread opposite the toasting side. It can be used to increase the ambient temperature of the toaster without operating to achieve a certain level of toasting in terms of temperature.

The method enters a toasting level evaluation sub-process 114 which is performed iteratively until it is determined that the bread has been toasted to the desired toasting level. This sub-process 114 begins at 116 by acquiring a digital image of the bread with a camera. Acquisition of the digital image at 116 may further include IR filtering. IR filtering may be performed physically using the camera's IR lens or it may be performed digitally in the image acquisition process by the camera. In either case, the digital image acquired at 116 is an image showing the bread received in the toaster without IR excitation emitted from the heat source. For example, illumination of the toasting surface from 110 by white light also helps to acquire this image, and the auxiliary light saturates the effect of the light emitted by the heat source.

At 118 , an image mask is acquired. In an example, the static or default image mask may be stored locally on the toaster's processor. The static image mask may be the same mask for all foods or different static masks may be stored for different types of foods (eg English muffins, bagels, sliced buns, buns). If the identification of the food is known, a corresponding static mask can be selected and used. In another example, a dynamic image mask may be generated from the image acquired at 116 . In an example, such a dynamic image mask may be created by modifying the static image mask as described above. Once a dynamic image mask is created, in an example it may be used throughout the toasting determination process, while in other examples the dynamic mask may be iteratively updated during subsequent cycles of the imaging process. The image mask may illustratively exclude all parts of the digital image that are not part of the food, and the image mask limits the part of the digital image data that is evaluated to determine the bread's toasting level.

In an example, a build-in value calculated according to Equation 1 above may be generated for a static mask that determines a portion/region of digital image data that is evaluated when determining the build-in value. Thus, if a dynamic mask is used, which is a different area of the digital image data for which the result is used, a mask compensation factor (MC) may be needed to maintain an accurate determination. The mask compensation factor may be calculated based on optical spectral measurements from the digital image using first a static mask and then a dynamic mask.

here:

SMAR = Static Mask Average Red value

SMAG = Static Mask Average Green value

SMAB = Static Mask Average Blue value

DMAR = Dynamic Mask Average Red value

DMAG = Dynamic Mask Average Green value

DMAB = Dynamic Mask Average Blue value

At 124 , a current toasting level of the food surface is determined from the amount of light reflected from the toasting surface and captured in the digital image from the camera. The image mask concentrates analysis on the part of the acquired digital image that provides the most information about the toasting level determination. As mentioned previously, not all spectra of light returned in a digital image are used, and some spectra may be slightly weighted compared to spectra of other lights. In addition, the acquired digital image is determined by blocking the portion of the acquired digital image that is attributed to the bread and comparing the non-bread portion of the image to the previous image so that the image is not detected by the camera or discontinuities between the images due to the movement of the bread in the toaster. The image is evaluated using an image tearing mask at 126 to determine if it is indicative of an image acquisition error. The image tearing mask evaluation returns an instruction on whether to reject the digital image acquired during this cycle of process 114 or use the image within process 114 .

If an image is used, the raw build value is calculated according to Equation 1 described above using, for example, a weighted determination of the amount of light in the test spectrum. Referring further to Equation 1, the reference brightness (RB _BX ) of bread in each test spectrum is obtained from the initial digital image. This reference brightness is used for each iteration of the raw build value. For each subsequently acquired digital image approved by the image tearing mask evaluation at 126 , the current brightness (CB _BX ) of the bread in each test spectrum is acquired from the acquired image. As described in more detail herein, the temperature in the toaster, particularly the temperature of the light source in the toaster, can change the light intensity output from the light source. This is corrected for the raw build value calculated using Equation 1 including the brightness compensation factor (BF _NBX ) for each light source in the test spectrum of light.

In an example, the raw build value may be used as the current toasting level of the food product determined at 124 from the amount of light determined in the test spectrum, test spectra, or weighted test spectrum according to equation (1). In another example, this raw build value can be converted to the current toasting level by applying a function of the form, illustratively:

The function for determining the final build value may exemplarily be linear, exponential, or logarithmic to the raw build value, putting the raw build value on the same scale as the toasting level model or definition.

At 128 , the converted toasting level is compared to the received desired toasting level value and it is determined whether toasting is complete. When the toasting process is complete and the desired toasting level value has been achieved, at 130 actuates to expel bread from the toaster so that the toaster does not exceed the desired toasting level or burn toasting bread, thereby rapidly terminating the toaster operation.

If the desired level of toasting has not yet been achieved, the sub-process 114 is repeated by acquiring a new digital image 116 and repeating the evaluation steps described above. In an exemplary embodiment, one cycle of sub-process 114 is performed every 250 milliseconds, although in alternative embodiments the cycle between digital image acquisition and evaluation can be lengthened or shortened while remaining within the scope of the present disclosure. will recognize that Accordingly, sub-process 114 is repeated until a desired toasting level of the bread is achieved and it is determined that the bread is released from the toaster.

Optionally, at 132 a dynamic boundary mask is computed to evaluate any surface area change in the toasting surface due to the toasting operation by comparing the current digital image to a previously acquired digital image and evaluating the change in pixel values between the two images. . As previously mentioned, some embodiments may use a standardized static image mask, compute a dynamic mask for use throughout the toasting process, or update the image mask during the toasting process. If the area of the bread shrinks, these shrinkage portions will appear as areas of change in the large image that exceed any exceptional amount of change due to toasting between any two images subsequently acquired. Areas of change due to bread shrinkage are added to the dynamic mask updated at 118 to provide a dynamic mask that addresses this bread shrink potential.

It will be appreciated that embodiments of method 100 may include more or fewer steps than those presented and described above. In addition to method features as described above, additional control processes may be implemented within method 100 to further refine and/or control the outcome of the processes as described in greater detail herein.

In an exemplary embodiment, the process includes an initialization and heating residence time between when the heat source is started and when the first digital image is acquired. In an exemplary embodiment, a residence time of 4 to 5 seconds is used prior to acquiring an initial reference image of the bread for toasting evaluation. In embodiments, one or more measures or relationships may be used to evaluate a determined return light for a current level of toasting. In exemplary embodiments, two or more measures or relationships may be used to indicate a range of toasting levels. In one embodiment, each toasting level is provided with a separate function to define the returned light and toasting level, whereas in another embodiment, one function is provided with two or more toasting levels (eg, bright and intermediate toasting levels), wherein the at least one other function is used to indicate progress to one or more other toasting levels (eg, dark toasting levels).

As previously mentioned, heat from a heat source can affect the intensity of the light generated by the light source. These changes in light intensity can be registered in image processing such as additional toasting or slow toasting. In an exemplary embodiment, an additional camera may be added to the toaster and may be directed to a light source or neutral portion of the toaster, such as an insulator or other structure on the wall between the light source and the heating element. Readings from this camera or light sensor provide a reading or measurement of the intensity of light output from the light source. Measurements of light intensity can be used as a compensation factor to ensure a consistent assessment of toasting levels despite variations in output light intensity by the light source. This brightness compensation factor (BF _NBX ) is exemplarily calculated as follows for each light source/test spectrum:

In calculating the brightness compensation factor, the initial digital image is used to calculate the reference brightness (RB _NBX ) in each test spectrum. This is exemplarily done by using a portion or portions of an initial digital image that is known to contain no food. In an example, this portion may include an area otherwise obscured by an image mask when evaluating the toasting level of the food product. The brightness compensation factor is the ratio of the obtained current brightness (CB _NBX ) to the reference brightness for the current digital image. The current brightness is calculated for each test spectrum using the same portion or portions of the current digital image used for the initial digital image. In the example of the use of the brightness compensation factor described above, the compensation factor also determines the build value to maintain accuracy in the event of a malfunction of one of the light sources, for example, burnout or failure of one of the light sources to function properly. You can also adjust it.

As discussed above, some examples of toaster 10 may include a heat source 12B arranged to provide additional thermal energy to the toasting system while providing little or no toasting of the food itself. In one example, heat source 12B may include a resistive wire. The resistance of the wire, and thus the current through the wire, may change with the temperature of the resistive wire. Accordingly, an ammeter or other current sensor may be used to determine the temperature of the heat source 12B and the heat source 12B operating at or within a set point temperature. Furthermore, the control of the lower heater temperature may be based on the following equation:

here:

TLH = Temperature Lower Heater

TTLH = Target Temperature Lower Heater

t _I = Idle Time in seconds

t _t = Time Since Last Measurement

In yet another exemplary embodiment of the method, one or more backup processes that provide additional calculations for toasting completion and exit therefrom can prevent the bread from burning or toasting too much and thus avoiding the bread being discharged from the toaster by ignoring it. can be expressed differently. One such backup process is a "forward progress" algorithm that compares build-level changes between subsequent evaluation cycles. In an exemplary embodiment, the moving average of build-up level changes (eg, over five previous evaluation cycles) should remain positive for the continuing toasting process. Conceptually speaking, the toasting process is expected to accelerate to a point of saturation (eg, burning), at which point the rate of change in the build-up level becomes flat or negative. Thus, as long as the toasting process follows the expected log pattern, the toasting process will continue.

In another exemplary embodiment, a latent heat model is used to perform alternative calculations of independent toasting levels from digital images acquired by the camera. Thus, the latent heat model backup method can provide control over the toasting operation in the event of an image acquisition error by the camera, image processing error, or malfunction of the camera and/or light source required for image acquisition. In another embodiment, the toaster may instead operate in a latent heat control mode if one or more errors prevent control based on digital image acquisition described above. In latent heat control, the system energy can be exemplarily represented by the following equation:

where T _t = Toast Time in seconds

In the latent heat model control, the toasting time is adjusted based on the latent heat stored in the toaster. It is calculated by tracking how much energy was entered into the toasting system and how much energy was lost from the heating cycle based on the hypothesized toasting system cooling curve. In this embodiment, the expected toasting time is calculated based on the desired toasting level and the heat already in the toasting system and the continuous input of thermal energy to the toaster during the toasting operation. If this expected toasting time is exceeded, or is exceeded by a predetermined threshold percentage or a threshold percentage based on the desired toasting level, the system ignores the toasting process and releases the bread so that the bread is toasted or burnt too much. it can be prevented Latent heat control is described in greater detail in Applicants' pending US patent application Ser. No. 16/556,826 entitled "Latent Heat Toaster Control," which is incorporated herein by reference in its entirety.

4 shows an exemplary embodiment of a toaster 10 oriented horizontally. 5 also shows in schematic view a toaster 10 oriented horizontally. It will be appreciated that like reference numerals between these figures and FIG. 1 refer to like components and are used herein to incorporate descriptions of components as previously provided. Yet another embodiment may incorporate the features described herein with respect to FIGS. 4 and 5 and features previously described with respect to FIG. 1 in addition to the other disclosures provided herein to arrive at embodiments within the scope of the present disclosure. It will be appreciated that combinations are possible.

The toaster 10 shown in FIGS. 4 and 5 illustratively includes at least one conveyor 44 . As shown in FIG. 4 , the toaster 10 may include two conveyors 44 arranged to operate in parallel with respect to each other. These conveyors 44 may extend through the toaster 10 . Conveyor 44 may be operable to advance food (not shown) to a predetermined position within toaster 10 relative to the previously described IR source contained therein. It will be appreciated that each conveyor may have at least one associated IR source within the toaster 10 .

5 provides an example of additional features that may be found in the example of toaster 10 . Conveyor 44 of FIG. 5 operates only to deliver food into toaster 10 . Conveyor 44 may include dividers 46 extending outwardly from conveyor 44 to help hold the food thereon and provide regular spacing and/or ordering for food 16 placed thereon. can

The toaster 10 may include a safety door 48 that serves multiple purposes. In a first purpose, the safety door blocks user access to the toasting area 50 to the IR source 12 . This protects the user so that when the safety door 48 is closed, the corresponding limit switch 52 is activated so that the IR source 12 is activated and heated. When the safety door 48 is opened, the limit switch 52 is also opened to prevent the IR source 12 from being excited.

Also, if food is misplaced on the conveyor 44 as shown in FIG. 5 , the misplaced food 16 may engage the exterior of the safety door 48 , thereby causing the Further advancing of the food product 16 is prevented despite advancing. Further advance of conveyor 44 is misplaced until food 16 is properly aligned with both conveyor 44 and safety door 48 in such a way that food 16 is received into toasting area 50 during the next toasting operation. Conveyor 44 will advance for cooked food 16 .

In the example shown in FIG. 5 , the toasting area 50 is further defined by a floor heater or tray 54 supporting the food in the toasting area 50 with respect to the IR source 12 . Upon determining that the desired level of toasting has been achieved in the food product, the floor heater and/or tray 54 is pivoted to discharge the toasted food 16 onto an outlet ramp 56 that is dispensed from the toaster 10 or otherwise open. The example shown and described above with respect to FIGS. 4 and 5 is an example of placing toasted food in a position similar to the position in which the food was initially placed in the toaster and in the same orientation as the food was loaded into the toaster 10 (eg, It can illustratively have the advantage of returning functionally to the toasting surface (with the toasting surface facing up).

6 and 7 show another exemplary embodiment of a toaster 10 in which the toaster 10 is arranged in an inclined orientation. 6 shows the toaster 10 of this embodiment, and FIG. 7 is a cross-sectional view taken along line 7-7 of FIG. 4 and 5 , like reference numerals in these figures identify like elements between the embodiments, and some of the features described in connection with the embodiments of FIGS. 6 and 7 . It will be appreciated that all or all may be used together in combination with features as described above or as further described herein to arrive at yet another exemplary embodiment of a toaster that is within the scope of the present disclosure.

As best seen in FIG. 7 , the toasting area 50 as well as many of the working components of the toaster 10 are angled. In this embodiment, the user may insert food directly into the opening 60 as selectively blocked by a safety door 48 . The inner heating region 50 of the opening 60 is also inclinedly arranged and defined by a toasting IR source 12a and a heating IR source 12b. The heating IR source 12b also forms the bottom tray 54 . Cradle 58 is exposed at the inner end of toasting area 50, containing food within toasting area 50 and a toasting IR source 12a and a heated IR source (12a) for consistent and repeatable toasting. 12b) serves to help sort food. When the toasting operation is complete, the bottom tray 54 containing the heating IR source 12b slides in the direction of the arrow 62 inside the toaster 10 so that the tray 54 does not interfere with the toasted food. move The toasted food falls from the toasting area 50 onto the exit ramp 56 for dispensing from the toaster 10 .

Citations are made herein to a number of references. The cited references are incorporated herein by reference in their entirety. In the event of any discrepancy between the definition of a term in a cited reference and the definition of a term in this specification, the term should be interpreted based on the definition set forth herein.

In the description above, certain terminology has been used for brevity, clarity, and understanding. Since such terminology is used for purposes of description and is intended to be interpreted broadly, no unnecessary limitations are to be drawn therefrom beyond the requirements of the prior art. The various system and method steps described herein can be used alone or in combination with other systems and methods. It is anticipated that various equivalents, alternatives and modifications may be made within the scope of the appended claims.

The functional block diagrams, operational sequences, and flow diagrams provided in the drawings represent example architectures, environments, and methodologies for carrying out novel aspects of the present disclosure. For simplicity of description, a methodology included herein may be in the form of a functional diagram, sequence of operations, or flow diagrams and may be described as a series of operations, although a methodology includes some operations shown herein, in accordance with this specification. It should be understood and appreciated that the order of acts is not limited as it may occur in a different order and/or concurrent with other acts described and described. For example, those skilled in the art will understand and appreciate that a methodology could alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all acts illustrated in a methodology may be required for a new implementation.

This written description uses examples to disclose the invention, including the best mode, and to enable those skilled in the art to make and use the invention. The patentable scope of the present invention is defined by the claims, and may include other examples contemplated by those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or include equivalent structural elements that differ in substance from the literal language of the claims. do.

Claims (20)

a support configured to hold food;
an infrared (IR) source arranged relative to the support and operable to direct IR energy to food on the support;
a light source arranged relative to the support and operable to illuminate food on the support while the IR source is operative to direct the IR energy;
a camera operative to capture a digital image of the food product on the support;
a processor for receiving images from the camera, wherein the processor analyzes successive images received from the camera and operates an IR source based on the analysis to achieve a predetermined toasting level of the food product, wherein the processor is configured to: A toaster that activates the IR source to end directing the IR energy when a level is reached. The toaster of claim 1 , wherein the light source is operative to illuminate the support and the processor analyzes the digital image from the camera to determine the presence of food on the support. The toaster of claim 1 , wherein the processor determines a current toasting level of the food product from successive images received from the camera based on the amount of light in at least one test spectrum in each successive image. 4. The method of claim 3, wherein the processor analyzes the digital image from the camera to determine an initial color of the food product on the support, and the processor analyzes the at least one test spectrum analyzed by the processor to determine a current toasting of the food product. The toaster, which determines the weight. 5. The toaster of claim 4, wherein the at least one test spectrum comprises a green light test spectrum and a red light test spectrum. The toaster of claim 5 , wherein the weight for the red light test spectrum increases as the darkness of the initial color of the food increases. The toaster of claim 3 , wherein the current toasting level of the food product is determined by the processor further based on a brightness compensation factor for the at least one test spectrum. 8. The method of claim 7, wherein the processor calculates at least one brightness compensation factor based on a reference brightness for at least one test spectrum determined from a portion of an initial image of food obtained by the camera, the portion comprising no food. and the at least one brightness compensation factor is further calculated based on the current brightness for the at least one test spectrum determined from the same portion of a subsequent image from the camera. 9. The method of any preceding claim, further comprising an image tearing mask, wherein the processor applies the image tearing mask to each successive image received from the camera and applies the image tearing mask. A toaster, which passes or rejects an image for use in determining the current toasting of a food product based on it. 10. The image received from the camera according to any one of claims 1 to 9, further comprising a predetermined static mask, wherein the processor limits the portion of the received image analyzed to determine a current toasting of the food product. Applying a static mask to the, toaster. 11. The method of any preceding claim, wherein the processor further determines a dynamic mask based on the at least one image of the food product received from the camera, wherein the dynamic mask is the calculated at least one of the food product in the at least one image. a toaster comprising one boundary and wherein the processor applies a dynamic mask to the image received from the camera to limit the portion of the received image analyzed to determine a current toasting of the food product. 12. The processor of any preceding claim, further comprising an ejector operatively coupled to the support and to the processor, the processor removing the bread product from proximity to the IR source when a predetermined toasting level is reached. The toaster, which operates the ejector to do so. 13 . The toaster according to claim 1 , wherein the IR source is annularly configured and the camera is positioned at the center of the IR source. The toaster of claim 13 , wherein the camera comprises a wide-angle lens. The toaster of claim 14 , wherein the camera is recessed from the outer surface of the IR source in a direction away from the bread product. The toaster of claim 13 , wherein the light source is positioned in the center of the IR source and adjacent to the camera. 17. The toaster of any preceding claim, further comprising a forced gas source and a duct between the camera and the IR source to create a forced gas flow around the camera, the duct opening around the camera. A method of toasting using the toaster of any one of claims 1 to 17, comprising:
holding the food product on the support against an infrared (IR) source;
actuating the IR source to direct IR energy to the food product on the support;
illuminating the food on the support;
acquiring a digital image of the food on the support with a camera;
analyzing successive images acquired by the camera to determine a current toasting level of the food product based on an amount of light in at least one test spectrum in each digital image acquired by the camera;
determining when a current toasting level of the food product reaches a predetermined toasting level of the food product; and
activating the IR source to end directing the IR energy to the food product when a predetermined toasting level of the food product is reached. 19. The method of claim 18,
determining the initial color of the food by analyzing the initial image from the camera; and
based on the initial color, determining a weight for the at least one test spectrum to determine a current toasting level of the food product. 20. The method of claim 19,
determining a reference brightness for at least one test spectrum from a portion of an initial image that does not include food;
determining a current brightness for at least one test spectrum from the same portion of a subsequent image from the camera;
calculating a brightness compensation factor for at least one test spectrum from the reference brightness and the current brightness; and
and further using a brightness compensation factor for the at least one test spectrum to calculate a current toasting level of the food product.

Images